Various methods have been employed in the checkup or diagnosis of diseases. For example, biochemical or biological examination is carried out by collecting blood invasively and conducting diagnosis based on the components, diagnostic markers and cells contained in the blood; pathological examination is conducted by conducting the biopsy of cancer tissue or the examination for abnormality on cellular level invasively; and the examination of urine, stool or saliva involves the collection thereof. In carrying out these method, a doctor, nurse or clinical analyst must collect blood with a syringe, must extirpate a tissue (affected site) from a living body with a sharp-edged knife or must collect an object of examination or diagnosis in a special case in cooperation with a patient.
In particular, mammary cancer is known to be a cancer which is difficult to find in an early stage, though it is one of the major cancers which tend to increase. Although the diagnosis of mammary cancer is conducted by internal examination, palpation, mammography (X ray), detection of tumor markers [such as carcinoembryonic antigen (CEA), .alpha.-fetoprotein (AFP), cancer antigen (CA15-3) and various saccharide antigens], ultrasonography or the like, these methods do not always exhibit a high diagnosis efficiency. For example, a phyma-free cancer gives neither pain nor subjective symptoms in early stages, so that patients therewith cannot find abnormality in many cases. Meanwhile the diagnosis based on a tumor marker such as CEA, CA15-3 or AFP is conducted by determining the concentration thereof in blood by radioimmunoassay (RIA) or enzyme immunoassay (EIA) and the concentration of such a tumor marker in blood serves as an indication of the prognosis or therapy effect of a cancer which is advanced considerably or metastasizing to the lymph node. However, it is very difficult to conduct the early diagnosis of primary mammary cancer by determining the concentration, because the positive rate for an early cancer is extremely low.
There were therefore many cases wherein the cancer had been advanced or had metastasized to the lymph node with the result of unwilling mastectomy.
Accordingly, the early diagnosis of mammary cancer is little conducted by the assay of concentration of a tumor marker in blood, but depends on palpation or inquiry. Further, the diagnosis with X ray (such as mammography) involves the exposure of a living body to a considerably high dose of X ray and the reading of a mammograph necessitates much experience and high skill. Further, cytodiagnosis involves the determination of a questionable site. However, it is difficult to find an extremely small affected site by current methods easily and simply.
The assay of specific substances contained in a serum, blood or biopsy specimen is generally conducted by a physiochemical or biochemical method, immuno-assay, a pathological method or the like. Therefore, the assay cannot be conducted at the site of medical services, so that the above specimen must be entrusted to an institution fitted with examination equipment or a special laboratory technician. Accordingly, it takes many days to know the result of the assay, which is problematic particularly in cases necessitating immediate treatment.
On the other hand, atopic dermatitis is steadily increasing owing to change in the living environment, lowering in the adaptation of a living body and lowering in the natural immunity, becoming a socially significant problem. In particular, atopic diseases are extremely prevalent, so that it is said that there are one or two (latent) patients therewith per ten persons in Japan. However, the cause of the diseases has not sufficiently been elucidated as yet and the diagnosis and therapy of them depend on the macroscopic or experimental sense of a doctor in many cases.
Blood specimen collection or biopsy is problematic to patients in that the use of a needle of injection, a syringe, a sharp-edged knife or radiation gives greater or lesser fear or pain and the patients must go to a suitable institution. Further, the assay of urine or stool is disadvantageous in that the place and behavior for collecting it are limited.
Meanwhile, there have already been known (1) medical patches containing drugs, e.g., salicylic anti-inflammatory agent or angina pectoris remedy such as nitroglycerin; diagnostic patches useful in the patch test for skin irritation; and those which are useful in the detection of allergen for determining the sensitizer of allergic dermatitis or the like (all of these patches are characterized by releasing a drug or other substance) and (2) pads for capturing the blood or exudate discharged from a living body or for disinfecting wound, for example, gauze, pad for wound and sanitary napkin. However, there has not been known any diagnostic patches which can effectively trap a substance or liquid discharged from the skin or mucosa and on which the assay of the substance or liquid can be conducted. In particular, there has not known any idea of applying a patch directly to the skin and the breast including the nipple and conducting the assay on the patch.
It has been known that various biocomponents are secreted from the skin or mucosa. However, the amount of an object for the assay secreted from the skin is very small and the sampling of a liquid on the skin is difficult, though the assay of a liquid substance secreted from the skin according to the prior art involves the pipetting of the liquid substance. For these reasons, there has been no accurate method for assaying a liquid substance secreted from the skin qualitatively or quantitatively has been found.
Further, it has also been known that a (liquid) secretion is discharged from the nipple as observed in the case of papillary hypersecretion. However, the sampling and assay of the secretion were problematic. It was reported in Inaji et al., "Igaku no Ayumi (Advance in Medicine)", 134, 575, 1985 that the secretion from the nipple was pipetted and examined for CEA by immunoassay, and as a result, CEA was found to be useful in the diagnosis for cancer.
Further, Mochida et al. reported in Japanese Patent Laid-Open Gazette Nos. 250069/1989, 176466/1990 and 280061/1990 that a secretion from the nipple can be analyzed for a tumor-associated antigen (such as CEA) qualitatively or semiquantitatively by sampling a slight amount of a secretion from the nipple and dropping it onto a liquid-nonpermeable sheet on which a specific antibody against the antigen is immobilized. However, this method involves the pipetting of a secretion from the nipple and the application of the secretion on a liquid-nonpermeable sheet (solid phase), so that it has a problem of being applicable only to a patient with papillary hypersecretion wherein the amount of secretion from the nipple is about 0.2 to 50 .mu.l. Further, these patent documents disclose a vague idea of detecting CEA by bringing a sheet having a CEA-specific antibody immobilized thereon into contact with the nipple, but are silent on the specific technique or method for carrying out such detection. In particular, they are completely silent on the idea of detecting CEA or other objective substance by applying a diagnostic patch which comprises a liquid-permeable adsorption carrier and a water-absorbing and adsorbent membrane to capture and immobilize a secretion which cannot be detected as a liquid at least macroscopically.